Improve code quality

10 files changed, 58 insertions, 56 deletions

diff --git a/sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java b/sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java
index b8baf578ee8..81f0cf06059 100644
--- a/sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java
+++ b/sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/sensor/internal/SensorContextTester.java
@@ -260,7 +260,6 @@ public class SensorContextTester implements SensorContext {
   public Integer lineHits(String fileKey, int line) {
     return sensorStorage.coverageByComponent.getOrDefault(fileKey, Collections.emptyList()).stream()
       .map(c -> c.hitsByLine().get(line))
-      .flatMap(Stream::of)
       .filter(Objects::nonNull)
       .reduce(null, SensorContextTester::sumOrNull);
   }
@@ -274,7 +273,6 @@ public class SensorContextTester implements SensorContext {
   public Integer conditions(String fileKey, int line) {
     return sensorStorage.coverageByComponent.getOrDefault(fileKey, Collections.emptyList()).stream()
       .map(c -> c.conditionsByLine().get(line))
-      .flatMap(Stream::of)
       .filter(Objects::nonNull)
       .reduce(null, SensorContextTester::maxOrNull);
   }
@@ -283,7 +281,6 @@ public class SensorContextTester implements SensorContext {
   public Integer coveredConditions(String fileKey, int line) {
     return sensorStorage.coverageByComponent.getOrDefault(fileKey, Collections.emptyList()).stream()
       .map(c -> c.coveredConditionsByLine().get(line))
-      .flatMap(Stream::of)
       .filter(Objects::nonNull)
       .reduce(null, SensorContextTester::maxOrNull);
   }
diff --git a/sonar-plugin-api-impl/src/main/java/org/sonar/api/impl/ws/SimpleGetRequest.java b/sonar-plugin-api-impl/src/main/java/org/sonar/api/impl/ws/SimpleGetRequest.java
index 153788121a3..08132cf0cf0 100644
--- a/sonar-plugin-api-impl/src/main/java/org/sonar/api/impl/ws/SimpleGetRequest.java
+++ b/sonar-plugin-api-impl/src/main/java/org/sonar/api/impl/ws/SimpleGetRequest.java
@@ -68,7 +68,7 @@ public class SimpleGetRequest extends Request {
 
   @Override
   public boolean hasParam(String key) {
-    return params.keySet().contains(key);
+    return params.containsKey(key);
   }
 
   @Override
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/DefaultInputFileTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/DefaultInputFileTest.java
index f052506340a..72ba4d2407b 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/DefaultInputFileTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/DefaultInputFileTest.java
@@ -156,14 +156,16 @@ public class DefaultInputFileTest {
     DefaultInputFile f1a = new DefaultInputFile(new DefaultIndexedFile("ABCDE", Paths.get("module"), MODULE_RELATIVE_PATH, null), (f) -> mock(Metadata.class));
     DefaultInputFile f2 = new DefaultInputFile(new DefaultIndexedFile("ABCDE", Paths.get("module"), "src/Bar.php", null), (f) -> mock(Metadata.class));
 
-    assertThat(f1).isEqualTo(f1);
-    assertThat(f1).isEqualTo(f1a);
-    assertThat(f1).isNotEqualTo(f2);
+    assertThat(f1)
+      .isEqualTo(f1)
+      .isEqualTo(f1a)
+      .isNotEqualTo(f2);
     assertThat(f1.equals("foo")).isFalse();
     assertThat(f1.equals(null)).isFalse();
 
-    assertThat(f1.hashCode()).isEqualTo(f1.hashCode());
-    assertThat(f1.hashCode()).isEqualTo(f1a.hashCode());
+    assertThat(f1)
+      .hasSameHashCodeAs(f1)
+      .hasSameHashCodeAs(f1a);
   }
 
   @Test
@@ -176,7 +178,7 @@ public class DefaultInputFileTest {
   public void checkValidPointer() {
     Metadata metadata = new Metadata(2, 2, "", new int[] {0, 10}, new int[] {9, 15}, 16);
     DefaultInputFile file = new DefaultInputFile(new DefaultIndexedFile("ABCDE", Paths.get("module"), MODULE_RELATIVE_PATH, null), f -> f.setMetadata(metadata));
-    assertThat(file.newPointer(1, 0).line()).isEqualTo(1);
+    assertThat(file.newPointer(1, 0).line()).isOne();
     assertThat(file.newPointer(1, 0).lineOffset()).isZero();
     // Don't fail
     file.newPointer(1, 9);
@@ -213,10 +215,10 @@ public class DefaultInputFileTest {
   public void checkValidPointerUsingGlobalOffset() {
     Metadata metadata = new Metadata(2, 2, "", new int[] {0, 10}, new int[] {8, 15}, 16);
     DefaultInputFile file = new DefaultInputFile(new DefaultIndexedFile("ABCDE", Paths.get("module"), MODULE_RELATIVE_PATH, null), f -> f.setMetadata(metadata));
-    assertThat(file.newPointer(0).line()).isEqualTo(1);
+    assertThat(file.newPointer(0).line()).isOne();
     assertThat(file.newPointer(0).lineOffset()).isZero();
 
-    assertThat(file.newPointer(9).line()).isEqualTo(1);
+    assertThat(file.newPointer(9).line()).isOne();
     // Ignore eol characters
     assertThat(file.newPointer(9).lineOffset()).isEqualTo(8);
 
@@ -250,7 +252,7 @@ public class DefaultInputFileTest {
     Metadata metadata = new FileMetadata(mock(AnalysisWarnings.class)).readMetadata(new StringReader("bla bla a\nabcde"));
     DefaultInputFile file = new DefaultInputFile(new DefaultIndexedFile("ABCDE", Paths.get("module"), MODULE_RELATIVE_PATH, null), f -> f.setMetadata(metadata));
 
-    assertThat(file.newRange(file.newPointer(1, 0), file.newPointer(2, 1)).start().line()).isEqualTo(1);
+    assertThat(file.newRange(file.newPointer(1, 0), file.newPointer(2, 1)).start().line()).isOne();
     // Don't fail
     file.newRange(file.newPointer(1, 0), file.newPointer(1, 1));
     file.newRange(file.newPointer(1, 0), file.newPointer(1, 9));
@@ -276,9 +278,9 @@ public class DefaultInputFileTest {
     Metadata metadata = new FileMetadata(mock(AnalysisWarnings.class)).readMetadata(new StringReader("bla bla a\nabcde\n\nabc"));
     DefaultInputFile file = new DefaultInputFile(new DefaultIndexedFile("ABCDE", Paths.get("module"), MODULE_RELATIVE_PATH, null), f -> f.setMetadata(metadata));
 
-    assertThat(file.selectLine(1).start().line()).isEqualTo(1);
+    assertThat(file.selectLine(1).start().line()).isOne();
     assertThat(file.selectLine(1).start().lineOffset()).isZero();
-    assertThat(file.selectLine(1).end().line()).isEqualTo(1);
+    assertThat(file.selectLine(1).end().line()).isOne();
     assertThat(file.selectLine(1).end().lineOffset()).isEqualTo(9);
 
     // Don't fail when selecting empty line
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/FileMetadataTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/FileMetadataTest.java
index 8fd67f6ed6b..ba1a19ca34c 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/FileMetadataTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/fs/internal/fs/FileMetadataTest.java
@@ -60,7 +60,7 @@ public class FileMetadataTest {
     FileUtils.touch(tempFile);
 
     Metadata metadata = new FileMetadata(analysisWarnings).readMetadata(new FileInputStream(tempFile), StandardCharsets.UTF_8, tempFile.getName());
-    assertThat(metadata.lines()).isEqualTo(1);
+    assertThat(metadata.lines()).isOne();
     assertThat(metadata.nonBlankLines()).isZero();
     assertThat(metadata.hash()).isNotEmpty();
     assertThat(metadata.originalLineStartOffsets()).containsOnly(0);
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultExternalIssueTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultExternalIssueTest.java
index 84f57635817..dc8a63ac101 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultExternalIssueTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultExternalIssueTest.java
@@ -67,7 +67,7 @@ public class DefaultExternalIssueTest {
         .at(inputFile.selectLine(1))
         .message("Wrong way!"))
       .forRule(RuleKey.of("repo", "rule"))
-      .remediationEffortMinutes(10l)
+      .remediationEffortMinutes(10L)
       .type(RuleType.BUG)
       .severity(Severity.BLOCKER);
 
@@ -75,8 +75,8 @@ public class DefaultExternalIssueTest {
     assertThat(issue.ruleKey()).isEqualTo(RuleKey.of("external_repo", "rule"));
     assertThat(issue.engineId()).isEqualTo("repo");
     assertThat(issue.ruleId()).isEqualTo("rule");
-    assertThat(issue.primaryLocation().textRange().start().line()).isEqualTo(1);
-    assertThat(issue.remediationEffort()).isEqualTo(10l);
+    assertThat(issue.primaryLocation().textRange().start().line()).isOne();
+    assertThat(issue.remediationEffort()).isEqualTo(10L);
     assertThat(issue.type()).isEqualTo(RuleType.BUG);
     assertThat(issue.severity()).isEqualTo(Severity.BLOCKER);
     assertThat(issue.primaryLocation().message()).isEqualTo("Wrong way!");
@@ -94,7 +94,7 @@ public class DefaultExternalIssueTest {
         .on(project)
         .message("Wrong way!"))
       .forRule(RuleKey.of("repo", "rule"))
-      .remediationEffortMinutes(10l)
+      .remediationEffortMinutes(10L)
       .type(RuleType.BUG)
       .severity(Severity.BLOCKER);
 
@@ -103,7 +103,7 @@ public class DefaultExternalIssueTest {
     assertThat(issue.engineId()).isEqualTo("repo");
     assertThat(issue.ruleId()).isEqualTo("rule");
     assertThat(issue.primaryLocation().textRange()).isNull();
-    assertThat(issue.remediationEffort()).isEqualTo(10l);
+    assertThat(issue.remediationEffort()).isEqualTo(10L);
     assertThat(issue.type()).isEqualTo(RuleType.BUG);
     assertThat(issue.severity()).isEqualTo(Severity.BLOCKER);
     assertThat(issue.primaryLocation().message()).isEqualTo("Wrong way!");
@@ -122,7 +122,7 @@ public class DefaultExternalIssueTest {
         .at(inputFile.selectLine(1))
         .message("Wrong way!"))
       .forRule(RuleKey.of("repo", "rule"))
-      .remediationEffortMinutes(10l)
+      .remediationEffortMinutes(10L)
       .severity(Severity.BLOCKER);
 
     assertThatThrownBy(() -> issue.save())
@@ -138,7 +138,7 @@ public class DefaultExternalIssueTest {
         .on(inputFile)
         .at(inputFile.selectLine(1)))
       .forRule(RuleKey.of("repo", "rule"))
-      .remediationEffortMinutes(10l)
+      .remediationEffortMinutes(10L)
       .type(RuleType.BUG)
       .severity(Severity.BLOCKER);
 
@@ -156,7 +156,7 @@ public class DefaultExternalIssueTest {
         .at(inputFile.selectLine(1))
         .message("Wrong way!"))
       .forRule(RuleKey.of("repo", "rule"))
-      .remediationEffortMinutes(10l)
+      .remediationEffortMinutes(10L)
       .type(RuleType.BUG);
 
     assertThatThrownBy(() -> issue.save())
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultIssueTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultIssueTest.java
index 25199bd9509..9f39ed11dfe 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultIssueTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/batch/sensor/issue/internal/DefaultIssueTest.java
@@ -71,7 +71,7 @@ public class DefaultIssueTest {
 
     assertThat(issue.primaryLocation().inputComponent()).isEqualTo(inputFile);
     assertThat(issue.ruleKey()).isEqualTo(RuleKey.of("repo", "rule"));
-    assertThat(issue.primaryLocation().textRange().start().line()).isEqualTo(1);
+    assertThat(issue.primaryLocation().textRange().start().line()).isOne();
     assertThat(issue.gap()).isEqualTo(10.0);
     assertThat(issue.primaryLocation().message()).isEqualTo("Wrong way!");
 
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MapSettingsTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MapSettingsTest.java
index 41c28b0529f..6b672fc7b3e 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MapSettingsTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MapSettingsTest.java
@@ -209,7 +209,7 @@ public class MapSettingsTest {
   public void default_number_values_are_zero() {
     Settings settings = new MapSettings();
     assertThat(settings.getInt("foo")).isZero();
-    assertThat(settings.getLong("foo")).isEqualTo(0L);
+    assertThat(settings.getLong("foo")).isZero();
   }
 
   @Test
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MultivaluePropertyTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MultivaluePropertyTest.java
index d7503e7765c..93f873b40ff 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MultivaluePropertyTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/config/internal/MultivaluePropertyTest.java
@@ -83,7 +83,7 @@ public class MultivaluePropertyTest {
   @Test
   @UseDataProvider("plains")
   public void trimFieldsAndRemoveEmptyFields_ignores_EmptyFields(String str) {
-    assertThat(trimFieldsAndRemoveEmptyFields("")).isEqualTo("");
+    assertThat(trimFieldsAndRemoveEmptyFields("")).isEmpty();
     assertThat(trimFieldsAndRemoveEmptyFields(str)).isEqualTo(str);
 
     assertThat(trimFieldsAndRemoveEmptyFields(',' + str)).isEqualTo(str);
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/AlwaysIncreasingSystem2Test.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/AlwaysIncreasingSystem2Test.java
index a96ff9579c0..b2c298427dc 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/AlwaysIncreasingSystem2Test.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/AlwaysIncreasingSystem2Test.java
@@ -97,7 +97,7 @@ public class AlwaysIncreasingSystem2Test {
         if (initialValue != null) {
           assertThat(now).isEqualTo(initialValue);
         } else {
-          assertThat(now).isGreaterThan(0);
+          assertThat(now).isPositive();
         }
         previousValue = now;
       } else {
diff --git a/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/WorkDurationTest.java b/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/WorkDurationTest.java
index 30e9219a1da..af1da5fabd5 100644
--- a/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/WorkDurationTest.java
+++ b/sonar-plugin-api-impl/src/test/java/org/sonar/api/impl/utils/WorkDurationTest.java
@@ -34,9 +34,9 @@ public class WorkDurationTest {
   @Test
   public void create_from_days_hours_minutes() {
     WorkDuration workDuration = WorkDuration.create(1, 1, 1, HOURS_IN_DAY);
-    assertThat(workDuration.days()).isEqualTo(1);
-    assertThat(workDuration.hours()).isEqualTo(1);
-    assertThat(workDuration.minutes()).isEqualTo(1);
+    assertThat(workDuration.days()).isOne();
+    assertThat(workDuration.hours()).isOne();
+    assertThat(workDuration.minutes()).isOne();
     assertThat(workDuration.toMinutes()).isEqualTo(ONE_DAY_IN_MINUTES + ONE_HOUR_IN_MINUTES + ONE_MINUTE);
     assertThat(workDuration.hoursInDay()).isEqualTo(HOURS_IN_DAY);
   }
@@ -44,7 +44,7 @@ public class WorkDurationTest {
   @Test
   public void create_from_value_and_unit() {
     WorkDuration result = WorkDuration.createFromValueAndUnit(1, WorkDuration.UNIT.DAYS, HOURS_IN_DAY);
-    assertThat(result.days()).isEqualTo(1);
+    assertThat(result.days()).isOne();
     assertThat(result.hours()).isZero();
     assertThat(result.minutes()).isZero();
     assertThat(result.hoursInDay()).isEqualTo(HOURS_IN_DAY);
@@ -60,15 +60,15 @@ public class WorkDurationTest {
     WorkDuration workDuration = WorkDuration.createFromMinutes(ONE_MINUTE, HOURS_IN_DAY);
     assertThat(workDuration.days()).isZero();
     assertThat(workDuration.hours()).isZero();
-    assertThat(workDuration.minutes()).isEqualTo(1);
+    assertThat(workDuration.minutes()).isOne();
 
     workDuration = WorkDuration.createFromMinutes(ONE_HOUR_IN_MINUTES, HOURS_IN_DAY);
     assertThat(workDuration.days()).isZero();
-    assertThat(workDuration.hours()).isEqualTo(1);
+    assertThat(workDuration.hours()).isOne();
     assertThat(workDuration.minutes()).isZero();
 
     workDuration = WorkDuration.createFromMinutes(ONE_DAY_IN_MINUTES, HOURS_IN_DAY);
-    assertThat(workDuration.days()).isEqualTo(1);
+    assertThat(workDuration.days()).isOne();
     assertThat(workDuration.hours()).isZero();
     assertThat(workDuration.minutes()).isZero();
   }
@@ -79,17 +79,17 @@ public class WorkDurationTest {
     WorkDuration workDuration = WorkDuration.createFromLong(1L, HOURS_IN_DAY);
     assertThat(workDuration.days()).isZero();
     assertThat(workDuration.hours()).isZero();
-    assertThat(workDuration.minutes()).isEqualTo(1);
+    assertThat(workDuration.minutes()).isOne();
 
     // 1 hour
     workDuration = WorkDuration.createFromLong(100L, HOURS_IN_DAY);
     assertThat(workDuration.days()).isZero();
-    assertThat(workDuration.hours()).isEqualTo(1);
+    assertThat(workDuration.hours()).isOne();
     assertThat(workDuration.minutes()).isZero();
 
     // 1 day
     workDuration = WorkDuration.createFromLong(10000L, HOURS_IN_DAY);
-    assertThat(workDuration.days()).isEqualTo(1);
+    assertThat(workDuration.days()).isOne();
     assertThat(workDuration.hours()).isZero();
     assertThat(workDuration.minutes()).isZero();
   }
@@ -113,26 +113,27 @@ public class WorkDurationTest {
 
   @Test
   public void convert_to_working_long() {
-    assertThat(WorkDuration.createFromValueAndUnit(2, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY).toLong()).isEqualTo(2l);
-    assertThat(WorkDuration.createFromValueAndUnit(4, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).toLong()).isEqualTo(400l);
-    assertThat(WorkDuration.createFromValueAndUnit(10, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).toLong()).isEqualTo(10200l);
-    assertThat(WorkDuration.createFromValueAndUnit(8, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).toLong()).isEqualTo(10000l);
-    assertThat(WorkDuration.createFromValueAndUnit(2, WorkDuration.UNIT.DAYS, HOURS_IN_DAY).toLong()).isEqualTo(20000l);
+    assertThat(WorkDuration.createFromValueAndUnit(2, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY).toLong()).isEqualTo(2L);
+    assertThat(WorkDuration.createFromValueAndUnit(4, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).toLong()).isEqualTo(400L);
+    assertThat(WorkDuration.createFromValueAndUnit(10, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).toLong()).isEqualTo(10200L);
+    assertThat(WorkDuration.createFromValueAndUnit(8, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).toLong()).isEqualTo(10000L);
+    assertThat(WorkDuration.createFromValueAndUnit(2, WorkDuration.UNIT.DAYS, HOURS_IN_DAY).toLong()).isEqualTo(20000L);
   }
 
   @Test
   public void add() {
     // 4h + 5h = 1d 1h
-    WorkDuration result = WorkDuration.createFromValueAndUnit(4, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).add(WorkDuration.createFromValueAndUnit(5, WorkDuration.UNIT.HOURS, HOURS_IN_DAY));
-    assertThat(result.days()).isEqualTo(1);
-    assertThat(result.hours()).isEqualTo(1);
+    WorkDuration result = WorkDuration.createFromValueAndUnit(4, WorkDuration.UNIT.HOURS, HOURS_IN_DAY)
+      .add(WorkDuration.createFromValueAndUnit(5, WorkDuration.UNIT.HOURS, HOURS_IN_DAY));
+    assertThat(result.days()).isOne();
+    assertThat(result.hours()).isOne();
     assertThat(result.minutes()).isZero();
     assertThat(result.hoursInDay()).isEqualTo(HOURS_IN_DAY);
 
     // 40 m + 30m = 1h 10m
     result = WorkDuration.createFromValueAndUnit(40, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY).add(WorkDuration.createFromValueAndUnit(30, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY));
     assertThat(result.days()).isZero();
-    assertThat(result.hours()).isEqualTo(1);
+    assertThat(result.hours()).isOne();
     assertThat(result.minutes()).isEqualTo(10);
     assertThat(result.hoursInDay()).isEqualTo(HOURS_IN_DAY);
 
@@ -161,8 +162,9 @@ public class WorkDurationTest {
     assertThat(result.hoursInDay()).isEqualTo(HOURS_IN_DAY);
 
     // 30m - 20m = 10m
-    assertThat(WorkDuration.createFromValueAndUnit(30, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY).subtract(WorkDuration.createFromValueAndUnit(20, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY))
-      .minutes()).isEqualTo(10);
+    assertThat(
+      WorkDuration.createFromValueAndUnit(30, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY).subtract(WorkDuration.createFromValueAndUnit(20, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY))
+        .minutes()).isEqualTo(10);
 
     assertThat(WorkDuration.createFromValueAndUnit(10, WorkDuration.UNIT.MINUTES, HOURS_IN_DAY).subtract(null).minutes()).isEqualTo(10);
   }
@@ -171,7 +173,7 @@ public class WorkDurationTest {
   public void multiply() {
     // 5h * 2 = 1d 2h
     WorkDuration result = WorkDuration.createFromValueAndUnit(5, WorkDuration.UNIT.HOURS, HOURS_IN_DAY).multiply(2);
-    assertThat(result.days()).isEqualTo(1);
+    assertThat(result.days()).isOne();
     assertThat(result.hours()).isEqualTo(2);
     assertThat(result.minutes()).isZero();
     assertThat(result.hoursInDay()).isEqualTo(HOURS_IN_DAY);
@@ -183,13 +185,14 @@ public class WorkDurationTest {
     WorkDuration durationWithSameValue = WorkDuration.createFromLong(28800, HOURS_IN_DAY);
     WorkDuration durationWithDifferentValue = WorkDuration.createFromLong(14400, HOURS_IN_DAY);
 
-    assertThat(duration).isEqualTo(duration);
-    assertThat(durationWithSameValue).isEqualTo(duration);
+    assertThat(duration)
+      .isNotNull()
+      .hasSameHashCodeAs(duration)
+      .isEqualTo(duration);
+    assertThat(durationWithSameValue)
+      .hasSameHashCodeAs(duration)
+      .isEqualTo(duration);
     assertThat(durationWithDifferentValue).isNotEqualTo(duration);
-    assertThat(duration).isNotEqualTo(null);
-
-    assertThat(duration.hashCode()).isEqualTo(duration.hashCode());
-    assertThat(durationWithSameValue.hashCode()).isEqualTo(duration.hashCode());
     assertThat(durationWithDifferentValue.hashCode()).isNotEqualTo(duration.hashCode());
   }